Here's what rhymes with diachronic.
chronic ionic ironic tonic chorionic colonic sonic conic phonic iconic laconic bionic harmonic tectonic demonic mnemonic sardonic ganglionic isotonic platonic synchronic diatonic subsonic daemonic avionic acetonic electronic embryonic hegemonic ultrasonic hypertonic planktonic polyphonic symphonic catatonic telephonic monophonic supersonic histrionic monotonic pathognomonic hydroponic infrasonic quadraphonic quadrophonic architectonic stereophonic philharmonic microelectronic Words that almost rhyme with diachronic
comic atomic ergonomic economic anatomic autonomic genomic diatomic agronomic taxonomic subatomic astronomic tragicomic uneconomic gastronomic macroeconomic microeconomic socioeconomic logic rollick topic chaotic erotic caloric folic gothic tropic boric frolic hayrick cosmic toxic aortic aquatic exotic garlic neurotic biologic caustic melodic carbolic necrotic pyloric atopic biotic cathodic dialogic euphoric formic gnostic iambic karmic meiotic myopic robotic sclerotic bardic cirrhotic folkloric acrostic ecologic seraphic strophic carsick placekick diagnostic alcoholic periodic hydraulic diastolic geologic isotropic narcotic pathologic prognostic psychotic etiologic idiotic isotopic phenolic psychologic yardstick agnostic anabolic anarchic anoxic cathartic cytologic fibrotic lethargic nephrotic bucolic diabolic hierarchic heartsick rhapsodic workaholic allegoric subtopic chopstick noncaloric shambolic chocoholic chocaholic horologic historic symbolic patriotic hydrochloric philosophic despotic episodic hypnotic macroscopic neurologic systolic ascorbic hyperbolic morphologic parabolic semiotic synoptic basaltic gynecologic meteoric nontoxic oligarchic orthodontic pedagogic psychotropic quixotic thrombotic demagogic vitriolic gyroscopic macrobiotic sophomoric theosophic nonnarcotic subtropic aetiologic gynaecologic seismologic astronautic metabolic microscopic antibiotic apostolic physiologic catastrophic cytotoxic histologic anisotropic atherosclerotic endoscopic metaphoric pharmacologic spasmodic symbiotic melancholic polymorphic telescopic antarctic arthroscopic homoerotic microcosmic xenophobic subarctic meteorologic shopaholic prehistoric philanthropic immunologic metamorphic hematologic peristaltic bacteriologic fluoroscopic kaleidoscopic unpatriotic misanthropic nonalcoholic posthypnotic haematologic anthropomorphic epidemiologic spectroscopic stereoscopic stroboscopic submicroscopic electroscopic antispasmodic